The present disclosure relates to a non-transitory computer-readable medium that is configured to improve image quality of image data.
In related art, a technology to improve image quality of image data is known. For example, an image forming apparatus is known that detects a maximum position at which frequency is high in comparison to surrounding portions, from a density histogram generated based on an original document that has been read. When three or more maximum positions are detected, the image forming apparatus detects the maximum position at which the density is highest as an image peak position, detects the maximum position at which the density is lowest as a background peak position, and detects the maximum position that exists in an area between the image peak position and the background peak position as a show-through peak position. The image forming apparatus performs binarization on the image data, using an intermediate density between an image section and a show-through section as a threshold value, and provides the image data after density adjustment to an optical writing unit. Thus, an image with a density that is equal to or lower than that of the show-through section is inhibited from being reproduced on a recording paper.
For example, in a known image processing apparatus, a reduced color image is generated using an input image that has been converted to a low-resolution image. Candidate regions for a flat color region (FCR) are extracted by integrating adjacent pixels that are assigned to the same representative color from the reduced color image. The candidate regions are determined again using a higher resolution image than the reduced color image. The final FCR is determined by detecting a boundary of the FCR. A representative color of the determined FCR is selected. When the selected representative color is a color close to a pure color, the representative color is replaced by the pure color (for example, white). The input image is overwritten by the FCR, and thus image regeneration is performed.